St Albans, Hertfordshire
Rear extension planning drawings in St Albans
We plan and build rear extensions for homeowners in St Albans. Measured survey, design options, planning drawings and the application, handled for you. Start with a free site visit, then a written price once the design is agreed.
We cover St Albans (AL1 and AL2) as part of our Hertfordshire work. Rear extension applications in Hertfordshire are householder applications, which councils aim to decide within about eight weeks.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
What do rear extension planning drawings cost in St Albans?
As a guide, £1,000–£2,500 including VAT for a single-storey rear extension, or £2,000–£3,500 for a two-storey scheme. A householder planning application in England costs £548 (£575 for applications made from 8 December 2026), and a lawful development certificate for proposed work costs half the householder fee. Your written price follows a measured survey and an agreed design, so it reflects your house, not an average.
Do you need planning permission for a rear extension in St Albans?
Whether your rear extension in St Albans needs a planning application depends on its size, your house and any local restrictions.
A two-storey rear extension can be permitted development in England only if it projects no more than 3 metres, stays at least 7 metres from the rear boundary, matches the existing roof pitch and has obscure-glazed upper side windows. In practice most double-storey rear extensions go through a householder planning application.
Councils aim to decide householder applications within 8 weeks of validation, and prior approval within 42 days.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. We check your house's planning history and any conservation area before drawing, so the route is clear before you spend on plans.
What are homes in St Albans like to extend?
Post-war semis and newer estates are typical of St Albans, and many have room for a full-width extension. Shrinkable clay is common in the East of England, so foundations near trees and hedges are designed to NHBC-style depth guidance.
How a rear extension in St Albans comes together
Look round and measure
A free visit to see the back of the house, measure it, check the drains and boundaries and hear what you need.
Drawings and budget
Floor plans and elevations for the options, each with a guide price.
Paperwork handled
Planning, prior approval or permitted development, Building Regulations approval, structural design and party wall notices are all handled by us.
Written price, then build
Once the design and approvals are in place, you get a fixed written price and programme, and we build through to sign-off.
Rear extension planning drawings near St Albans
We also build rear extensions in nearby Abbots Langley (4.7 miles) and Harpenden (4.7 miles).
- Rear extension planning drawings in Abbots Langley
- Rear extension planning drawings in Harpenden
- Rear extension planning drawings in Hatfield
- Rear extension planning drawings in Hemel Hempstead
- Rear extension planning drawings in North Watford
Other work in St Albans:
FAQ
Rear extension planning drawings questions in St Albans
What postcode areas do you cover around St Albans?
Including AL1 and AL2, and the surrounding Hertfordshire area.
Who will build my extension?
Vetted building teams working under contract to us. Your contract is with S&K Property Investments and Improvement Ltd for the design and the build.
Do neighbours get consulted?
Yes for a full application: the council writes to them or puts up a site notice.
Can I live at home while the extension is built?
Usually yes. Most of the work is outside until the back wall is opened near the end, and that stage is screened off.
Do you handle building control in St Albans?
Yes. We apply to the council or a registered building control approver and hand over the completion certificate.
Do I need a party wall agreement?
In England, usually yes if the extension is on or near a shared boundary or the foundations are close to a neighbour's building. We serve the notices.